Keying device for electronic organs



June 167 D. G. OLSON KEYING DEVICE FOR ELECTRONIC ORGANS Filed Sept. 28, 1964 .S'rkme OSClLLATDR OSCILLATOR To AMPLIFHER I I l :L-

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A IQ AMPLJFIER Avon: 12", Tune AMPLIFIE. SPEAKER OSCILLRT R INVENTOR. DB (/10 6-. 04 50/\/ 3M 6? M A 7'7'0/P VEY MILLATBE CW United States Patent 3 327,045 KEYING DEVICE FGR ELECTRONIC ORGANS David G. ()lson, W219 S7216 Crowbar Drive, Muskego, Wis. 53150 Filed Sept. 28, 1964, Ser. No. 399,713 2 Claims. (Cl. 841.01)

ABSTRACT OF THE DISCLOSURE or it may through the use of separate electrically isolated parts mounted on the common movable member present separate electrical paths between any desired combination of fixed contacts. The movable member may be normally in contact with the fixed contacts when the playing key is inoperative and be moved away from them when the playing key is operated, or it may be normally away from the fixed contacts when the playing key is inoperative and may be moved into contact with the fixed contacts when the key is operated.

This invention relates to electronic keying systems for musical instruments such as electronic organs.

In electronic organs, it is common to switch signal impulses from a source of generation such as an oscillator, into a collecting circuit or bus bar from which the impulses maybe ultimately passed to an amplifier and speaker Where they are heard as sound. The switching takes place when a key on the keyboard is depressed by a player. To provide an instrument of considerable flexibility from a musical standpoint, it is necessary to employ several separate switching circuits under each key with as many .as nine being not uncommon. In larger instruments, this number can increase up to fifteen or twenty required switches for each key. It is also necessary to have multiple connections to a single oscillator since one oscillaotr may serve several keys, and these connections are normally made through resistances.

It is an object of this invention to substantially reduce the cost of the switching circuits while at the same time increasing the number of possible switches which may be associated with a single key.

It is another object of this invention to provide a means of connecting a signal source such as an oscillator to several difierent switching circuits through resistances in an economical manner.

Other and further objects of the invention will appear as the description proceeds, reference being had to the accompanying drawing, in which:

FIG. 1 is a schematic of the circuit employed in the invention showing one contact and one key.

FIG. 2 is a schematic of the circuit employed in the invention showing two sources of signal each connected to two keys.

FIG. 3 is a perspective of a key coupled with one type of contact diagram.

FIG. 4 illustrates an etched circuit board comprising a portion of the circuit, and having etched circuits on both sides of the board.

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 4.

FIG. 6 is a similar view taken on line 6-6 of FIG. 4.

FIG. 7 is a side view in elevation of a key and a plurality of contacts.

FIG. 8 is an inverted plan view of an etched circuit board.

FIG. 9 is a view partly in section and partly in elevation taken on line 99 of FIG. 7.

Referring more particularly to the drawing, an oscillator 10 is connected to a bus bar 15 through resistor 12 and resistor 13. A wire 14 connects at one end to the junction of resistors 12 and 13 and at the other end to the shorting bar 17 which also is connected to ground through the wire 16. When the shorting bar 17 is in the position shown, no signal will reach bus bar 15 since the signal will pass from the oscillator through resistor 12, through the wire 14, through the shorting bar 17 and thence through the wire 16 to ground. When the shorting bar 17 moves to the position shown by the dotted line, wire 14 is no longer connected to ground and the signal will pass through resistor 12 and resistor 13 to the bus bar 15 and then to the amplifier and speaker circuits where it will be heard as sound.

In FIG. 2, two oscillators 20 and 21 are shown, each generating the same frequency but differing in wave shape and thus tone quality. Two key circuits are shown, one for one keyboard of an electronic organ and one for the other keyboard.

Flute oscillator 20 is connected to bus bar 29 through resistors 22 and 23 for one manual, and to bus bar 39 through resistors 34 and 35 for the other manual or keyboard. The string oscillator 21 is similarly connected to bus bar 30 through resistances 25 and 26 for one keyboard and to bus bar 38 through resistances 31 and 32 for the other keyboard. The bus bar 29 collects all the flute signals for one keyboard and the bus bar 30 collects all the string signals for the same keyboard. When shorting bar 28 is moved to the position indicated by the dotted line by depressing the key, flute signal passes from oscillator 20 to bus bar 29 and string signal passes from oscillator 21 to bus bar 30. When these bus bars are connected to appropriate audio amplifiers and speakers both sources of tone are heard. The same action takes place when shorting bar 37 is moved to the position indicated by the dotted line by depressing a key on the other keyboard. If both keys are pressed, more signal will reach the amplifiers and the sound will be louder.

FIG. 3 shows a single key 42 pivoting on rod 44 and held in a level position by spring 43. Shorting bar 45 made of metal such as copper connects the three contacts 46 together when the key is inoperative. Signal from the flute oscillator 40 passes to ground through resistor 48, the wire leading to contact 46. The contacts are mounted in a block of insulating material 47 such as wood or plastic, such contact blocks being commonly found in pipe organs. The string oscillator signal also passes to ground through resistor 53 and contact 46. When the key 42 is depressed by the player, the shorting bar 45 leaves the contacts 46 so that the signals no longer pass to ground. If stop switch 50 is closed, flute tone will pass through resistor 49 to amplifier 51 and speaker 52 Where it will be heard as sound. If stop switch 55 is closed string tone will pass through resistor 54 to amplifier 56 and speaker 57 where it will be heard as sound. While separate amplifiers and speakers are shown for flute and string tone, it is understood that one amplifier and speaker only might be employed. More tone sources may be employed and more stop switches, and the number shown is only by way of illustration and in no way limits the scope of the invention.

FIG. 4 shows a printed circuit board 60 on which etched circuits appear on the face and on the reverse side.

An oscillator 62 is connected to circuit element 61. Shown mounted are resistors 63 on one face of the board 60 and the resistor 66 on the reverse face. The junction of the two resistors is another circuit element 64 to which is also connected a wire 65 which is connected to the key contact. The bus bar 67 is another circuit element on the reverse side of the board and is connected by a wire 68 to stop switches. Although only three connections are shown, it is understood that any number might be obtained by enlarging the board and increasing the number of connection points 64 and the bars 67. Since etched circuits maybe made by economical methods, a large number of such circuits may be produced on a single circuit board at relatively low cost. While carbon resistors are shown, other types of resistors may be used including resistance paint which may be silk-screened on the circuit board or applied by other methods further reducing the cost of producing this element of the circuit.

FIG. is a printed circuit board 70 on which are etched the contacts 72 and the ground connection 71. The contacts 72 are shorted to the ground connection 71 by the shorting bar 73 when the key is inoperative. Moving the shorting bar 73 away from the circuit board will disconnect the contacts 72 from the ground connection 71 and produce the same action as the contact in FIG. 3. While only ten contacts are shown, any number may be easily produced by spacing closer together or enlarging the dimensions of the circuit board. The contacts may run in any direction as well, but are limited by the width of a single key if run from top to bottom.

While only a few of the many forms the circuit may take are illustrated, it is understood that any system employing multiple contacts which are electrically and physically connected together when a key is inoperative and are separated from each other when a key is depressed falls within the scope and intent of this invention. It is also possible to use this contact system for keying voltage to energize the oscillators by putting the voltage on the bus bars. Depressing a key would allow the voltage to pass through a pair of resistors to the oscillator to cause oscillation. This circuit is also suitable for keying voltage to gating devices used to pass signal from an oscillator to a collection bus. The configuration of the resistive elements in an X-Y coordinate system 'is a part of the invention.

It will be understood that the device is capable of many modifications in structure and design without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent of the United States, is:

1. A signal switching device for use in electrical musical instruments, comprising a source of electrical oscillations of musical frequencies, a load circuit for converting the electrical oscillators from said source into musical sound vibrations, a keying device having a plurality of stationary contacts, a movable member actuated by the playing key, said movable member making electrical and physical contact with said stationary contacts such that all of said stationary contacts are electrically common through contact with said movable member when said movable member is in one of its two positions, and said stationary contacts are electrically isolated from each other when said movable member is in the other of its two positions.

2. The same as claim 1 except that said movable member making physical contact with said stationary contacts such that said stationary contacts may be connected together in any desired pattern through the use of individual electrically conductive parts mounted on said movable member, said conductive parts being electrically isolated from each other.

References Cited UNITED STATES PATENTS 2,559,510 6/1962 Campbell 84-1.01

ARTHUR GAUSS, Primary Examiner.

D. D. FORRER, Assistant Examiner. 

1. A SIGNAL SWITCHING DEVICE FOR USE IN ELECTRICAL MUSICAL INSTRUMENTS, COMPRISING A SOURCE OF ELECTRICAL OSCILLATIONS OF MUSICAL FREQUENCIES, A LOAD CIRCUIT FOR CONVERTING THE ELECTRICAL OSCILLATORS FROM SAID SOURCE INTO MUSICAL SOUND VIBRATIONS, A KEYING DEVICE HAVING A PLURALITY OF STATIONARY CONTACTS, A MOVABLE MEMBER ACTUATED BY THE PLAYING KEY, SAID MOVABLE MEMBER MAKING ELECTRICAL AND PHYSICAL CONTACT WITH SAID STATIONARY CONTACTS SUCH THAT ALL OF SAID STATIONARY CONTACTS ARE ELECTRICALLY COMMON THROUGH CONTACT WITH SAID MOVABLE MEMBER WHEN SAID MOVABLE MEMBER IS IN ONE OF ITS TWO POSITIONS, AND SAID STATIONARY CONTACTS ARE ELECTRICALLY ISOLATED FROM EACH OTHER WHEN SAID MOVABLE MEMBER IS IN THE OTHER OF ITS TWO POSITIONS. 